WHEN WE VISIT HENRY DOORLY ZOO AND AQUARIUM -- WE MIGHT NOT THINK ABOUT ALL THE HARD WORK HAPPENING BEHIND THE SCENES. KETV NEWSWATCH SEVEN'S AMANDA CRAWFORD SHOWS US -- A SPECIAL RELATIONSHIP BETWEEN ONE ANIMAL AND TRAINER. AND WHAT'S ABOUT TO CHANGE. IT'S OUR FASCINATION --(Addie look, here comes another one, (gorilla runs by) whoa! ) THAT PROMPTS THESE GUYS TO SHOW OFF. BUT BELOW THIS CAGE --(Station. (tombo stands up, whistle) good boy ) THE SHOW IS MORE HEARTFELT. TRAINERS DEDICATE HOURS TEACHING THE GORILLAS. TEAMWORK BUILT ON TRUST -- (dan: Tub!) THAT SOMETIMES -- TRANSFORMS TO FRIENDSHIP. (dan houser: Yeah, Tub was born in Columbus actually, in 1985) TUBBY CAME TO OMAHA WHEN HE WAS FIVE DAYS OLD.(dan houser: He's actually settled down a lot since his younger years, he was much more aggressive like these younger boys are) TRAINING WITH DAN HOUSER -- FOR 29 YEARS. (dan houser: Just to be accepted by an animal into their social group...that'll make a keeper's day, you know that's a big deal ) DAN'S WATCHED TUBBY GROW INTO A 430 POUND SILVERBACK SO WELL BEHAVED...(He's gotten to be so good ) HE'S PERFECT FOR BREEDING --(dan houser: Anyway, Tub leaves Thursday... and...) IN PHILADELPHIA. (he's actually going to a real good situation) TUBBY'S MOVE MAKES HIM A SUCCESS STORY. (dan houser: I feel extremely good about what Omaha's done with the gorilla program and Tubby's an ambassador of that) BUT AFTER SO MANY YEARS TOGETHER --(reporter: Are you going to miss him? Houser: Yeah, I think so) IT'S A BITTERSWEET GOODBYE.(COVER LAST PART WITH VO OF TUBBY) (dan houser: He just shows Philadelphia how much Omaha can do with their gorillas just by looking at one gorilla, it's something to be really proud of) (Philadelphia's gonna like him )(stand up, amanda crawford: Dan's so attached to Tubby, he'll travel with him to Philadelphia. They fly out early Thursday morning -- Dan will sit in the back -- right next to Tubby's cage. Reporting in Omaha, Amanda Crawford, KETV Newswatch Seven.) DAN HOUSER